Objective—To determine the susceptibility of ducks
to avian pneumovirus (APV) of turkey origin.
Animals—30 Pekin ducks that were 2 weeks old.
Procedure—Ducks were assigned to 3 groups (10
ducks/group). Ducks of groups 1 and 2 were inoculated
(day 0) with 200 µl of cell-culture fluid containing
APV of turkey origin (105.5 median tissue-culture infective
dose/ml) by the oculonasal (group 1) or oral
(group 2) route. Ducks of group 3 served as noninoculated
control birds. Two ducks from each group were
euthanatized 3, 6, 9, 15, and 21 days after inoculation.
Blood samples, tissue samples from the lungs, trachea,
nasal turbinates, duodenum, diverticulum
vitellinum (Meckel's diverticulum), and cecum, and
swab specimens from the choana, cloaca, and trachea
were obtained from all birds during necropsy
and examined for APV by use of reverse transcriptase-
polymerase chain reaction (RT-PCR), virus isolation,
and histologic examination. Blood samples also
were examined for APV antibodies, using an ELISA.
Results—Tissue samples obtained up to 21 days after
inoculation had positive results when tested by use of
RT-PCR. Virus was isolated from nasal turbinates of
birds inoculated via the oculonasal route. Serum samples
obtained 15 and 21 days after inoculation had
positive results when tested for APV-specific antibody.
Clinical signs of disease were not observed in ducks
inoculated with APV of turkey origin.
Conclusions and Clinical Relevance—Ducks inoculated
with APV of turkey origin may not develop clinical
signs of disease, but they are suspected to play a
role as nonclinical carriers of APV. (Am J Vet Res
Objective—To compare molecular typing methods
for the differentiation of Salmonella enterica serovar
Enteritidis phage type (PT) 4 isolates that allowed for
the determination of their genetic relatedness.
Sample Population—27 Salmonella Enteritidis PT 4
strains isolated in the United States and Europe.
Procedure—Several molecular typing methods were
performed to assess their ability to genetically differentiate
among Salmonella Enteritidis PT 4 isolates.
Results of pulse-field gel electrophoresis (PFGE),
repetitive polymerase chain reaction (PCR) assay, 16S
rRNA gene sequencing, random amplification of polymorphic
DNA (RAPD), PCR-restriction fragment
length polymorphism of 16S rRNA, and antimicrobial
susceptibility were evaluated.
Results—Compared with results for other techniques,
results for the RAPD typing method with the
RAPD1 primer reveal that it was the most discriminatory
fingerprinting technique, and it allowed us to
cluster Salmonella Enteritidis PT 4 isolates on the
basis of their genetic similarity.
Conclusions and Clinical Relevance—This study
revealed the value of RAPD with the RAPD1 primer as
a tool for epidemiologic investigations of Salmonella
Enteritidis PT 4. It can be used in conjunction with PFGE
and phage typing to determine the genetic relatedness
of Salmonella Enteritidis isolates involved in outbreaks
of disease. A reliable and highly discriminatory method
for epidemiologic investigations is critical to allow investigators
to identify the source of infections and consequently
prevent the spread of Salmonella Enteritidis
PT 4. ( Am J Vet Res 2004;65:538–543)